1. Field of the Invention
The present invention relates to a projection display device.
2. Description of the Related Art
A projection display device includes: an illumination optical system that illuminates a plurality of light modulation elements with different color light; a combining optical system that combines a plurality of color light optically modulated by the light modulation elements to generate combined light; and a projection optical system that projects the combined light generated by the combining optical system. The illumination optical system includes a plurality of optical components such as a mirror, a lens, and a color separation element. Light emitted from a light source is separated into a plurality of color light after passing through the plurality of optical components of the illumination optical system, and is emitted to the light modulation element. Japanese Laid-open Patent Publication No. 2008-158274 is disclosed.
Incidentally, the optical component of the illumination optical system causes an object on a light incident side of the optical component to be imaged on a light emission side of the optical component. For example, if the optical component is a mirror, the optical component forms a mirror image of the object. In addition, if the optical component is a convex lens, the optical component forms an inverted image of the object. Therefore, in the case of an illumination optical system in which a type or the number of optical components arranged in each optical path of a plurality of color light is different, there is a possibility that a direction of the image formation on the light emission side of the projection optical system may be different for each color light.
There is a possibility that a deviation may be generated in illuminance distribution of the color light with which the light modulating element is irradiated due to a mounting error of the light source or a positional change of the light source or the like. When the deviation is generated in the illuminance distribution of the color light with which the light modulation element is irradiated in the case where the direction of image formation is different for each color light, there is a possibility that color unevenness may occur in an image projected by the projection optical system.